irqchip: crossbar: Check for premapped crossbar before allocating

If irq_of_parse_and_map is executed twice, the same crossbar is mapped to two
different GIC interrupts. This is completely undesirable. Instead, check
if the requested crossbar event is pre-allocated and provide that GIC
mapping back to caller if already allocated.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: https://lkml.kernel.org/r/1403766634-18543-3-git-send-email-r.sricharan@ti.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
index 20105bcdf408..51d4b878e5d6 100644
--- a/drivers/irqchip/irq-crossbar.c
+++ b/drivers/irqchip/irq-crossbar.c
@@ -51,6 +51,17 @@ static inline void crossbar_writeb(int irq_no, int cb_no)
         writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
 }
 
+static inline int get_prev_map_irq(int cb_no)
+{
+        int i;
+
+        for (i = 0; i < cb->int_max; i++)
+                if (cb->irq_map[i] == cb_no)
+                        return i;
+
+        return -ENODEV;
+}
+
 static inline int allocate_free_irq(int cb_no)
 {
         int i;
@@ -88,11 +99,16 @@ static int crossbar_domain_xlate(struct irq_domain *d,
 {
         unsigned long ret;
 
+        ret = get_prev_map_irq(intspec[1]);
+        if (!IS_ERR_VALUE(ret))
+                goto found;
+
         ret = allocate_free_irq(intspec[1]);
 
         if (IS_ERR_VALUE(ret))
                 return ret;
 
+found:
         *out_hwirq = ret + GIC_IRQ_START;
         return 0;
 }